Electric circuit interrupter



June 1939- K. BAUERSCHMIDT ELECTRIC CIRCUIT INTERRUFTER Filed 001:. 26, 1936 -Insulatio- Attorneg.

Patented June 13, 1939 UNITED STATES PATENT 'OFFICE ELECTRIC CIRCUIT INTERRUPTER New York Application October 26, 1936, Serial No. 107,711 In Germany November 7, 1935 3 Claims.

My invention relates to electric circuit interrupters, more particularly to circuit interrupters oi the type wherein contact separation occurs within a closely confined arc chamber defined by walls of insulating material having gas-emitting characteristics. In this type of circuit interrupter the insulating walls, when subjected to the arc upon separation of the contacts, emit gas in sufficient quantity to cause interruption of the arc.

A principal object of the present invention is the provision of an improved circuit interrupter of the aforesaid type wherein the application of the gas emitted from the insulating walls to the arc is rendered more effective.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to 20 and forming a part of this specification.

Referring to the drawing the single figure thereof is an elevational view partly in section of an electric circuit interrupter embodying the present invention.

25 As illustrated the relatively movable contact.

structure of the electric circuit interrupter is in ----'-the -open circuit position and comprises a relatively fixed contact structure I and a coacting movable tubular contact 2. The contact 2 is re- 30 ciprocally movable in a vertical direction as shown for making and breaking contact at I. The fixed contact structure I as shown is of the segmental type, and in the closed circuit position engages the outer periphery of the coacting end of the tubular '35 contact. The fixed contact structure is suitably mounted within a metallic housing 3, to which is connected the terminal member 4.

For the purpose of forming a closely confined arc chamber along the path of separation of said 1 40 contacts, a cylindrical sleeve-like insulating member 5 is suitably secured to a depending portion 3 of the fixed contact housing and is disposed in substantial alinement with the tubular contact 2. The cylindrical member is beveled at 5' for 45 the purpose of guiding the tubular contact 2 and said pin, said pin also having a comparatively close fit with respect to the tubular contact.

It will, therefore, be apparent that the insulating members 5 and 6, by reason of the concentric spacing thereof, form at I an annular space 5 through which the tubular contact 2 is closely guided for coacting with the fixed contact I. Th annular chamber 1 communicates with an airfilled chamber 8 which is formed within the casing 3- at the point of initial contact separation. 10

For the purpose of providing automatic centering of the pin 1 in case of misalinement of said pin and the tubular contact, there is provided means for resiliently centering the pin comprising a collar 9 which is suitably secured to the upper end of the pin and which seats on a cylindrical bearing l0 whichis mounted in the casing 3. The members 9 and I0 engage at the coacting surfaces thereof so as to form a universal bearing for the pin 6. A spring at ll seated within the upper part of the casing 3 and bearing on the collar 9 tends to center the insulating pin.

For the purpose of obtaining application of gas under pressure to the are upon opening of the circuit, at least one and preferably both of the insulating members 5 and 6 is composed of a material which is adapted to emit gas in appreciable quantity when subjected to the heat of an arc. Examples of insulating materials having such characteristics are fiber and urea compound.

In the circuit opening operation of the device the contacts are first separated due to lowering of the tubular contact 2 and an arc is formed within the chamber 8. As the contact separation progresses the arc is drawn within the closely' confined annular chamber 1. The arc, however, in acting on the insulating walls of the members 5 and 6 generates gas which builds up considerable pressure within the arc chamber. This ac- 40 tion tends to interrupt the arc. In the event that 'the arc persists throughout the length of the arc chamber a strong gas blast effect is obtained when the tubular contact 2 leaves the lower end of the arc chamber. This gas blast should finally and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric circuit interrupter comprising relatively movable contact structure including a tubular contact and a coacting contact, a casing including a cylindrical sleeve-like member composed of insulating material fixed with respect to said coacting contact and having an inner diameter slightly greater than said tubular contact and alined in telescopic relation therewith, said' coacting contact being mounted within said casing at a closed end thereof, and a pin member composed of insulating material positioned centrally of said cylindrical member and adapted to extend within said tubular contact in the closed circuit position thereof, said insulating pin being composed of material adapted to emit gas in appreciable quantity when subjected to the arc upon separation of said contact structure, said gas being expelled from said cylindrical member in thet direction of movement of said tubular. con- 2. An electric circuit interrupter comprising relatively movable contact structure including a tubular contact and a coacting contact, a cylindrical sleeve-like member composed of insulating material fixed with respect to said coacting contact and adapted to receive in close fitting relationship said tubular contact in the closedcircult position thereof, a pin member composed of insulating material disposed within and centrally of said cylindrical member and adapted to extend within and centrally of said tubular contact in said closed circuit position, and means for resiliently centering said pin member with respect to slight misalinement between said pin member and tubular contact.

3. An electric circuit interrupter comprising relatively movable contact structure including a tubular contact and a coacting contact, terminal structure forming a housing for said coacting contact, means defining a closely confined arc chamber along the path of separation of said contacts comprising a cylindrical sleeve-like member of and centrally of the bore of said tubular con-- tact, at least one of said insulating members being composed of a material adapted to emit gas in appreciable quantity when subjected to the are upon separation of said contact structure.

' KUNO BAUERSCHMJDT. 

